In Fallout, Nuka-Cola tends to play a background role. Dugan, an addict, can talk about the drink, but otherwise it has no direct effect on the storyline.
The drink has several minor uses for quests and items in Fallout 2. One of the three ingredients of a super stimpak as crafted by the artiste of the test tube known as Myron. Also, the Chosen One can use any sort of status-modifying drug to trigger a fatal heart attack in Big Jesus Mordino.
Shops in Klamath and the respective machines. The bottles can be obtained from vending machines by left-clicking on a Nuka-Cola machine and dragging the mouse to access the backpack and putting coins in the slot.
Some would have been found in the Environmental Protection Agency, in an ice chest on sub-level blue.
A few can be found in Peoria.
Nuka-Cola machines, other than for reasons of gameplay, restock every one to seven weeks. In Fallout Tactics, there is a special encounter with a man pedaling a bicycle cart. This is Phil, the Nuka-Cola dude, who claims via bubble text to be personally responsible for restocking the vending machines of the wasteland. An unlimited quantity of Nuka-Cola can be purchased in the Broken Hills bar (this may be explained indirectly by the Homebrewed Nuka-Cola recipe in Fallout: New Vegas).
Behind the scenes
During the 2008 E3 as a promotional item, people were given a real drinkable version of Nuka-Cola. It greatly resembles the 1950s look of the Coca-Cola brand bottles.
During 2015/2016 a real version of Nuka Cola Quantum could be purchased online and in Target stores worldwide.
The name of the Nuka-Cola creator, John-Caleb Bradberton, is an amalgamation of the inventors of Coca-Cola (John Pemberton) and Pepsi-Cola (Caleb Bradham).
Its logos, bottle designs, market crash, and even its name are heavily based on Coca-Cola.